Senior Front-End Software Development Engineer (UI Foundations)

📍 Job Overview

Job Title: Senior Front-End Software Development Engineer (UI Foundations)

Company: Criteo

Location: Bucharest, Romania

Job Type: FULL_TIME

Category: Front-End Engineering / UI Foundations

Date Posted: June 23, 2026

Experience Level: Senior (6+ years)

Remote Status: Hybrid

🚀 Role Summary

• Drive the technical vision and strategic roadmap for front-end development across Criteo by establishing and evolving common libraries, SDKs, and the Criteo Design System.

• Develop, maintain, and review foundational front-end frameworks, tooling, and components to ensure a seamless development experience for all Criteo front-end engineers.

• Collaborate closely with UX/UI designers and other engineering teams to enhance the design system, optimize web application performance, and promote best practices in UI/UX development.

• Act as a technical consultant and evangelist, guiding development teams on front-end topics, app performance, and the adoption of cutting-edge technologies and methodologies.

📝 Enhancement Note: This role is critical for establishing and maintaining a cohesive and efficient front-end development ecosystem at Criteo. The focus on "UI Foundations" signifies a platform-level responsibility, impacting numerous product teams and requiring strong technical leadership, architectural thinking, and cross-functional collaboration. The emphasis on SDKs, libraries, and design systems points towards a role that builds reusable assets and sets standards.

📈 Primary Responsibilities

• Define and execute the technical vision for Criteo's front-end development stack, focusing on scalability, maintainability, and developer productivity.

• Architect, develop, and maintain core front-end libraries, Software Development Kits (SDKs), and the Criteo Design System, ensuring high quality, robust code, and comprehensive documentation.

• Collaborate with UX and UI designers to evolve and enrich the design system, ensuring it aligns with user needs and Criteo's brand identity.

• Partner with product engineering teams to drive the adoption of the UI Foundations stack, providing guidance, support, and best practice evangelization.

• Optimize web applications for maximum speed, scalability, and performance, identifying and addressing bottlenecks across the front-end architecture.

• Conduct code reviews, provide constructive feedback, and mentor junior engineers to foster a culture of technical excellence and continuous improvement.

• Research and evaluate emerging front-end technologies and trends, making recommendations for integration to keep Criteo's stack cutting-edge and competitive.

• Troubleshoot and resolve complex front-end issues, providing expert-level support to development teams.

📝 Enhancement Note: The responsibilities highlight a senior-level expectation for strategic technical leadership, architectural contribution, and direct impact on developer productivity and product performance. The blend of direct development, collaboration, and evangelization is characteristic of a platform engineering role focused on empowering other engineers.

🎓 Skills & Qualifications

Education: Bachelor's degree in Computer Science, Engineering, or a closely related technical field.

Experience: A minimum of 6 years of professional experience in front-end software development, with a significant portion focused on building foundational libraries, frameworks, or design systems.

Required Skills:

• Deep proficiency in modern JavaScript/TypeScript, HTML5, and CSS3, with a strong understanding of semantic HTML and responsive design principles.

• Extensive experience with at least one modern front-end framework, with a strong preference for Angular given the technical environment.

• Demonstrated experience in developing and maintaining reusable UI components, libraries, or SDKs.

• Proficiency with version control systems, particularly Git, including branching strategies and collaborative workflows.

• Solid understanding of web performance optimization techniques, including lazy loading, code splitting, and asset optimization.

• Excellent problem-solving and debugging skills, with a meticulous attention to detail in code and user experience.

• Proven ability to collaborate effectively within a cross-functional team environment, including with designers and backend engineers.

• Strong verbal and written communication skills, capable of articulating technical concepts clearly to diverse audiences. Preferred Skills:

• Hands-on experience with Angular and TypeScript, aligning directly with the team's technical stack.

• Familiarity with building and integrating RESTful APIs, and proficiency in asynchronous request handling patterns.

• Experience with front-end build tools (e.g., Webpack, Rollup) and comprehensive knowledge of testing frameworks (e.g., Cypress, Playwright, Jest).

• Understanding of CI/CD pipelines and their role in front-end development workflows.

• Experience working within Agile/Scrum development methodologies, participating in sprints, stand-ups, and retrospectives.

• Familiarity with C# for minor usage within the technical environment.

• Exposure to UI/UX development principles and best practices.

📝 Enhancement Note: The requirement for 6+ years of experience, coupled with the focus on "foundations," strongly suggests this role is for a seasoned engineer capable of architectural thinking and setting technical direction. The explicit mention of Angular and TypeScript as preferred skills, alongside the team's tech stack, means candidates with this specific experience will have a significant advantage.

📊 Process & Systems Portfolio Requirements

Portfolio Essentials:

• Demonstrate contributions to open-source projects, reusable component libraries, or SDKs that showcase your ability to build scalable and maintainable front-end assets.

• Provide case studies or examples of projects where you significantly improved web application performance, scalability, or developer workflow efficiency.

• Showcase experience with design systems, including contributions to their development, implementation, or evolution, highlighting how they improve consistency and productivity.

• Include examples of well-documented code, API designs, or technical specifications that illustrate your ability to create clear and actionable resources for other developers. Process Documentation:

• Document your approach to designing and optimizing front-end workflows, emphasizing efficiency, collaboration, and adherence to best practices.

• Illustrate your methods for implementing and automating front-end development processes, including testing strategies, build pipelines, and deployment procedures.

• Detail how you measure and analyze the performance and impact of front-end systems and processes, using data to drive improvements and demonstrate ROI.

📝 Enhancement Note: For a role focused on "UI Foundations" and providing common libraries/SDKs, a portfolio is crucial. It should highlight not just individual coding skill but the ability to build for other developers. This means showcasing reusable code, robust documentation, and evidence of impact on team productivity and application performance.

💵 Compensation & Benefits

Salary Range: Based on industry benchmarks for Senior Front-End Software Engineers in Bucharest, Romania, with 6+ years of experience, the estimated annual salary range is €45,000 - €70,000 gross. This range can vary based on specific experience, negotiation, and Criteo's internal compensation bands.

Benefits:

• Hybrid Ways of Working: A flexible model blending home and in-office experiences, promoting work-life balance.

• Career Growth: Access to comprehensive learning, mentorship programs, and structured career development pathways.

• Wellbeing Support: Robust health benefits, wellness perks, and dedicated mental health support resources.

• Inclusive Culture: A diverse, inclusive, and globally connected team environment where contributions are valued.

• Competitive Compensation: Attractive salary with performance-based rewards, family-friendly policies, and potential for equity depending on role and level.

• Additional Benefits: Country-specific benefits may apply, enhancing overall compensation and support.

Working Hours: Typically 40 hours per week, with flexibility often provided within the hybrid work model to accommodate personal needs and project demands.

📝 Enhancement Note: Salary estimation for Bucharest, Romania, was based on data from reputable salary aggregators (e.g., Glassdoor, LinkedIn Salary) for similar roles and experience levels in the region, adjusted for the tech industry and senior position. Benefits are directly extracted from the provided text.

🎯 Team & Company Context

🏢 Company Culture

Industry: Criteo operates in the technology sector, specifically as a Commerce Intelligence Platform. They leverage proprietary commerce intelligence and AI decisioning to drive shopper relevance and business performance in online advertising and e-commerce.

Company Size: Criteo employs approximately 3,600 individuals globally, indicating a substantial, established organization with diverse opportunities.

Founded: Criteo was founded in 2005, positioning it as a mature tech company with a significant history and established market presence.

Team Structure:

• The UI Foundations team consists of six engineers, suggesting a focused, high-impact group within a larger engineering organization.

• This role will involve close collaboration with other front-end and full-stack developers, UX/UI designers, and platform engineers, indicating a highly cross-functional environment.

• The Senior Engineer is expected to provide a technical vision, implying a leadership or influential role within the team and potentially within the broader front-end community at Criteo. Methodology:

• Criteo emphasizes data-driven decision-making through its "Commerce Intelligence Platform" and "AI decisioning," suggesting a strong focus on analytics and performance measurement in all its operations.

• The company likely employs modern software development methodologies, with Agile/Scrum mentioned as a preferred qualification, indicating iterative development, collaboration, and continuous improvement.

• Focus on building common libraries, SDKs, and design systems points to a platform-centric approach to development, prioritizing reusability, standardization, and efficiency.

Company Website: http://www.criteo.com/ (Implied from domain) and http://techblog.criteo.com/ (Explicitly mentioned for R&D insights).

📝 Enhancement Note: The company context highlights Criteo's focus on AI and commerce intelligence, which translates to a data-driven approach in engineering. The UI Foundations team's role in building common assets implies a strong emphasis on developer experience and platform efficiency, mirroring best practices in large tech organizations.

📈 Career & Growth Analysis

Operations Career Level: This is a Senior Front-End Software Engineer position, specifically within a UI Foundations team. This level signifies a highly experienced individual contributor expected to provide technical leadership, architectural guidance, and mentorship. The role is not managerial but focuses on deep technical expertise and influence over development standards and practices across the company.

Reporting Structure: The engineer will be part of a team of six and will likely report to a Engineering Manager or Team Lead within the UI Foundations group. They will collaborate extensively with product teams, UX/UI designers, and other platform engineers.

Operations Impact: The impact of this role is significant, as the UI Foundations team directly influences the efficiency, consistency, and quality of front-end development across all of Criteo's products. By providing robust libraries, SDKs, and a design system, this role enables faster development cycles, improved application performance, and a more cohesive user experience for Criteo's clients and end-users.

Growth Opportunities:

• Technical Specialization: Deepen expertise in front-end architecture, design systems, and performance optimization, potentially becoming a recognized subject matter expert within Criteo and the broader industry.

• Leadership & Mentorship: Grow into a technical lead role, mentoring junior engineers, guiding architectural decisions, and influencing the front-end strategy for multiple product lines.

• Cross-functional Exposure: Gain broader understanding of Criteo's commerce intelligence platform by collaborating with various product engineering teams, potentially leading to opportunities in adjacent engineering domains.

• Industry Engagement: Contribute to Criteo's R&D blog and potentially represent the company at industry conferences, enhancing personal brand and professional network.

📝 Enhancement Note: The "UI Foundations" aspect positions this as a platform engineering role, which is a desirable career path for senior engineers looking to have broad impact without managing people directly. The growth opportunities lean into deepening technical expertise and influencing engineering culture.

🌐 Work Environment

Office Type: Criteo offers a hybrid work model, blending in-office and remote work. This suggests a dynamic environment that values both structured collaboration and individual flexibility.

Office Location(s): The primary location for this role is Bucharest, Romania. Criteo has a global presence, but this specific position is tied to their Bucharest office, offering opportunities for local networking and team cohesion.

Workspace Context:

• The hybrid model facilitates collaborative sessions in the office, fostering team synergy and knowledge sharing, while also allowing for focused work from home.

• The technical environment will likely be equipped with modern development tools and infrastructure necessary for cutting-edge front-end engineering, including powerful workstations and access to necessary software licenses.

• Opportunities for interaction with a diverse range of engineers, designers, and product managers will be frequent, promoting a rich learning and collaborative atmosphere.

Work Schedule: While a standard 40-hour work week is typical, the hybrid model likely offers some flexibility in daily scheduling, allowing engineers to balance project deadlines with personal commitments. The emphasis on performance and outcomes over strict hours is common in such tech environments.

📝 Enhancement Note: The hybrid model is a key aspect of Criteo's work environment, indicating a modern approach to workplace flexibility. For a senior role, this flexibility is often valued, alongside the opportunity to engage in in-person collaboration on critical architectural and design tasks.

📄 Application & Portfolio Review Process

Interview Process:

• Initial Screening: A brief call with a recruiter to assess basic qualifications, cultural fit, and interest in the role.

• Technical Interview(s): One or more in-depth technical interviews focusing on core front-end concepts, TypeScript, Angular, algorithms, data structures, and problem-solving. Expect coding challenges on a whiteboard or shared editor.

• System Design/Architecture Interview: A session focused on architectural thinking, where you'll discuss how to design scalable, maintainable front-end systems, libraries, or SDKs, likely involving whiteboarding. This is where your portfolio examples will be highly relevant.

• Team/Manager Interview: A discussion with the hiring manager and potentially team members to assess your experience, collaboration style, leadership potential, and alignment with Criteo's culture.

• Final Round: May involve a discussion with senior leadership or a final technical deep-dive.

Portfolio Review Tips:

• Curate Selectively: Choose 2-3 of your strongest projects that best demonstrate your experience with building reusable components, SDKs, design systems, or optimizing performance.

• Focus on Impact: For each project, clearly articulate the problem you solved, your specific contributions, the technologies used, and the measurable outcomes (e.g., performance improvements, developer productivity gains, adoption rates).

• Showcase Reusability: Highlight projects where you created modular, scalable, and well-documented code that could be reused by others.

• Technical Depth: Be prepared to walk through the code, explain architectural decisions, and discuss trade-offs made during development.

• Design System Experience: If you have experience with design systems, be ready to discuss their principles, how you contributed, and their benefits.

Challenge Preparation:

• Algorithm & Data Structures: Brush up on common algorithms (sorting, searching, graph traversal) and data structures (arrays, linked lists, trees, hash maps). Practice coding these efficiently in TypeScript.

• TypeScript & Angular: Review advanced TypeScript features and core Angular concepts (components, services, modules, RxJS, change detection).

• System Design: Prepare to discuss designing a component library, an SDK, or a front-end framework. Think about modularity, extensibility, error handling, testing strategies, and documentation.

• Performance Optimization: Be ready to explain how you would diagnose and fix performance issues in a web application (e.g., using browser developer tools).

• Behavioral Questions: Prepare examples using the STAR method (Situation, Task, Action, Result) to demonstrate your problem-solving, collaboration, and leadership skills.

📝 Enhancement Note: Given the role's focus on "foundations" and building for other developers, the interview process will heavily scrutinize architectural thinking, code quality, and the ability to create reusable, well-documented assets. The portfolio review is paramount for demonstrating these capabilities.

🛠 Tools & Technology Stack

Primary Tools:

• TypeScript: The primary language for front-end development, requiring deep understanding of its features and type safety.

• Angular: The core front-end framework for building applications and components. Expertise in Angular is highly desirable.

• CSS: Essential for styling and layout, including modern CSS features and potentially preprocessors or CSS-in-JS solutions.

• Git: The standard for version control, used for code management, collaboration, and tracking changes.

Analytics & Reporting:

• Performance Monitoring Tools: Likely includes browser developer tools (Lighthouse, Performance tab) and potentially APM solutions for front-end performance analysis.

• Testing Frameworks: Cypress and Playwright are explicitly mentioned for end-to-end testing, indicating a strong emphasis on automated quality assurance.

CRM & Automation:

• While not directly CRM-related, the role involves building tools and libraries that automate development processes and ensure consistency across applications.

• Build Tools: Implicitly, tools like Webpack or Rollup for bundling and optimizing code.

• CI/CD Tools: Likely integrated into the development workflow for automated testing and deployment.

• C#: Mentioned for minor usage, suggesting potential integration points or legacy systems that might require occasional interaction.

📝 Enhancement Note: The technology stack is clearly defined: TypeScript and Angular are central, with Cypress and Playwright highlighting a commitment to robust testing. C# usage is noted as minor, so deep expertise isn't required, but awareness is beneficial.

👥 Team Culture & Values

Operations Values:

• Developer Productivity: A core value, evident in the team's mission to build common libraries and SDKs that streamline development for others.

• Technical Excellence: High standards for code quality, performance, and maintainability, driven by experienced engineers and rigorous review processes.

• Collaboration: Strong emphasis on teamwork, knowledge sharing, and cross-functional partnerships with design and product teams.

• Innovation: Encouragement to stay abreast of industry trends and adopt cutting-edge technologies to keep Criteo's front-end stack modern and competitive.

• Impact-Driven: Focus on delivering tangible value through foundational components that improve the efficiency and quality of Criteo's products.

Collaboration Style:

• Cross-functional Integration: Regular interaction with UX/UI designers to refine the design system and with product engineers to ensure seamless adoption of the UI Foundations stack.

• Mentorship & Knowledge Sharing: A culture where senior engineers mentor junior colleagues, and knowledge is actively shared through code reviews, internal documentation, and potentially tech talks.

• Constructive Feedback: An environment that encourages open and honest feedback during code reviews and team discussions to drive continuous improvement.

📝 Enhancement Note: The culture revolves around empowering other developers through robust foundational tools. This implies a team that values building for scale, maintainability, and ease of use by their internal customers (other engineers).

⚡ Challenges & Growth Opportunities

Challenges:

• Driving Adoption: Convincing diverse engineering teams to adopt standardized libraries and design systems can be challenging, requiring strong communication, support, and demonstrated value.

• Balancing Innovation & Stability: Keeping the front-end stack cutting-edge while maintaining stability and backward compatibility for existing applications is a constant balancing act.

• Evolving Standards: The rapid pace of front-end development requires continuous learning and adaptation to new technologies and best practices, ensuring the foundations remain relevant.

• Cross-team Dependencies: Managing dependencies and ensuring alignment across numerous product teams that rely on the UI Foundations framework.

Learning & Development Opportunities:

• Deep Dive into Angular & TypeScript: Become an expert in these core technologies, potentially exploring advanced patterns and performance tuning.

• Design System Architecture: Develop advanced skills in architecting and scaling design systems to meet the needs of a large organization.

• Performance Engineering: Specialize in front-end performance optimization techniques and tooling.

• Technical Leadership: Grow into a role influencing technical strategy, mentoring teams, and driving best practices across the engineering organization.

• Industry Exposure: Opportunities to engage with the broader tech community through Criteo's R&D blog and potential conference participation.

📝 Enhancement Note: The challenges are typical for platform teams focused on enabling others. The growth opportunities highlight a clear path for technical mastery and leadership within the front-end domain.

💡 Interview Preparation

Strategy Questions:

• "Describe a time you designed and implemented a reusable front-end library or SDK. What were the key considerations, and what was the impact?" (Prepare to discuss architecture, documentation, and adoption metrics).

• "How would you approach optimizing the performance of a large-scale web application that is experiencing slow load times?" (Focus on diagnostic process, tools, and specific techniques for optimization).

• "Imagine you need to introduce a new design system to multiple product teams. What would be your strategy for ensuring adoption and buy-in?" (Discuss communication, training, support, and phased rollout).

• "How do you stay up-to-date with the latest front-end technologies and trends, and how do you evaluate their potential adoption?" (Highlight continuous learning habits and a structured evaluation process). Company & Culture Questions:

• "What interests you about Criteo's work in Commerce Intelligence and AI?" (Research Criteo's business and how front-end plays a role).

• "How do you see the UI Foundations team contributing to Criteo's overall mission?" (Connect the team's goals to company objectives).

• "Describe your ideal collaborative environment when working with designers and other engineers." (Emphasize communication, feedback, and shared goals). Portfolio Presentation Strategy:

• Structure: For each project, use a clear narrative: Problem -> Solution -> Your Contribution -> Technologies -> Impact/Results.

• Visuals: Use screenshots, diagrams, or live demos (if possible) to illustrate your work.

• Code Snippets: Be ready to show well-chosen, concise code examples that highlight key architectural patterns or complex logic.

• Metrics: Quantify the impact of your work whenever possible (e.g., "reduced load time by X%", "increased component reusability by Y%", "saved Z developer hours per sprint").

• Focus on Reusability: Emphasize how your work was designed for others to use, including documentation and ease of integration.

📝 Enhancement Note: Interview preparation should heavily focus on demonstrating experience with building foundational components, architectural thinking, and driving adoption. Portfolio presentation is key to validating these claims.

📌 Application Steps

To apply for this Senior Front-End Software Development Engineer position:

• Submit your application through Criteo's Workday careers portal.

• Tailor your Resume: Highlight specific experience with TypeScript, Angular, SDK/library development, design systems, and performance optimization. Quantify achievements where possible.

• Prepare Your Portfolio: Select 2-3 strong projects that showcase your ability to build reusable front-end assets and improve developer efficiency. Be ready to discuss them in detail.

• Practice Technical Questions: Review common front-end algorithms, data structures, TypeScript/Angular concepts, and system design principles relevant to building foundational libraries.

• Research Criteo: Understand Criteo's business as a Commerce Intelligence Platform and their R&D efforts via their tech blog to articulate your interest and cultural fit.

⚠️ Important Notice: This enhanced job description includes AI-generated insights and operations industry-standard assumptions. All details should be verified directly with the hiring organization before making application decisions.